Chris Digital Tools
Browse, organise, and export emails from a Gmail Takeout file
Reading a large mbox file straight off your disk relies on a browser feature called the File System Access API. It is only built into Chromium based browsers.
This tool does not add anything to the web. It does not upload your file, it does not send your emails anywhere, and there is no database sitting behind it. The mbox file you choose is read directly off your own computer, processed entirely inside your browser, and the zip it builds is written straight back to your downloads folder. Close the tab and nothing of yours remains anywhere except on your own machine.
This is another small tool built because I needed it myself. I had a mailbox to sort through and no appetite for installing a full mail client just to pull a handful of emails out as PDFs, so I built this instead. It stayed online afterwards in case it is useful to someone else with the same problem.
Select the .mbox file from your Gmail Takeout export. Large files, up to around 2GB, are read in chunks directly from your disk.
Export ready. Your download should begin automatically.